Self-calibrating method for measuring the density and velocity of sound from two reflections of ultrasound at a solid-liquid interface

A method for determining a fluid property comprising the steps of:

• delivering an ultrasound pulse to a member with a transducer, the member being comprised of a solid material and including a first surface opposite a second surface, the first surface being coupled to the transducer and the second surface being in contact with a fluid, the ultrasound pulse reflecting between the first surface and the second surface to provide a first ultrasound pulse echo series;
• detecting a multiplicity of the ultrasound pulse echoes of the echo series with the transducer;
• delivering an ultrasound pulse through a shear wave transducer, the shear wave transducer configured to provide a pulse at a predefined angle relative to the interface of said second surface and said fluid to obtain a second ultrasound pulse echo series;
• detecting a multiplicity of ultrasound pulse echoes of said second ultrasound pulse echo sound series with said shear wave transducer;
• determining a first value from the multiplicity of pulse echoes of the first ultrasound pulse echo series;
• determining a second value from the multiplicity of pulse echoes of the second ultrasound pulse echo series;
• and
• determining a physical property of the fluid utilizing said first and second values.